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//===--- EvalEmitter.cpp - Instruction emitter for the VM -------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "EvalEmitter.h"
#include "Context.h"
#include "Interp.h"
#include "Opcode.h"
#include "Program.h"
#include "clang/AST/DeclCXX.h"
using namespace clang;
using namespace clang::interp;
using APSInt = llvm::APSInt;
template <typename T> using Expected = llvm::Expected<T>;
EvalEmitter::EvalEmitter(Context &Ctx, Program &P, State &Parent,
InterpStack &Stk, APValue &Result)
: Ctx(Ctx), P(P), S(Parent, P, Stk, Ctx, this), Result(Result) {
// Create a dummy frame for the interpreter which does not have locals.
S.Current = new InterpFrame(S, nullptr, nullptr, CodePtr(), Pointer());
}
llvm::Expected<bool> EvalEmitter::interpretExpr(const Expr *E) {
if (this->visitExpr(E))
return true;
if (BailLocation)
return llvm::make_error<ByteCodeGenError>(*BailLocation);
return false;
}
llvm::Expected<bool> EvalEmitter::interpretDecl(const VarDecl *VD) {
if (this->visitDecl(VD))
return true;
if (BailLocation)
return llvm::make_error<ByteCodeGenError>(*BailLocation);
return false;
}
void EvalEmitter::emitLabel(LabelTy Label) {
CurrentLabel = Label;
}
EvalEmitter::LabelTy EvalEmitter::getLabel() { return NextLabel++; }
Scope::Local EvalEmitter::createLocal(Descriptor *D) {
// Allocate memory for a local.
auto Memory = std::make_unique<char[]>(sizeof(Block) + D->getAllocSize());
auto *B = new (Memory.get()) Block(D, /*isStatic=*/false);
B->invokeCtor();
// Register the local.
unsigned Off = Locals.size();
Locals.insert({Off, std::move(Memory)});
return {Off, D};
}
bool EvalEmitter::bail(const SourceLocation &Loc) {
if (!BailLocation)
BailLocation = Loc;
return false;
}
bool EvalEmitter::jumpTrue(const LabelTy &Label) {
if (isActive()) {
if (S.Stk.pop<bool>())
ActiveLabel = Label;
}
return true;
}
bool EvalEmitter::jumpFalse(const LabelTy &Label) {
if (isActive()) {
if (!S.Stk.pop<bool>())
ActiveLabel = Label;
}
return true;
}
bool EvalEmitter::jump(const LabelTy &Label) {
if (isActive())
CurrentLabel = ActiveLabel = Label;
return true;
}
bool EvalEmitter::fallthrough(const LabelTy &Label) {
if (isActive())
ActiveLabel = Label;
CurrentLabel = Label;
return true;
}
template <PrimType OpType> bool EvalEmitter::emitRet(const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
return ReturnValue<T>(S.Stk.pop<T>(), Result);
}
bool EvalEmitter::emitRetVoid(const SourceInfo &Info) { return true; }
bool EvalEmitter::emitRetValue(const SourceInfo &Info) {
// Method to recursively traverse composites.
std::function<bool(QualType, const Pointer &, APValue &)> Composite;
Composite = [this, &Composite](QualType Ty, const Pointer &Ptr, APValue &R) {
if (auto *AT = Ty->getAs<AtomicType>())
Ty = AT->getValueType();
if (auto *RT = Ty->getAs<RecordType>()) {
auto *Record = Ptr.getRecord();
assert(Record && "Missing record descriptor");
bool Ok = true;
if (RT->getDecl()->isUnion()) {
const FieldDecl *ActiveField = nullptr;
APValue Value;
for (auto &F : Record->fields()) {
const Pointer &FP = Ptr.atField(F.Offset);
QualType FieldTy = F.Decl->getType();
if (FP.isActive()) {
if (llvm::Optional<PrimType> T = Ctx.classify(FieldTy)) {
TYPE_SWITCH(*T, Ok &= ReturnValue<T>(FP.deref<T>(), Value));
} else {
Ok &= Composite(FieldTy, FP, Value);
}
break;
}
}
R = APValue(ActiveField, Value);
} else {
unsigned NF = Record->getNumFields();
unsigned NB = Record->getNumBases();
unsigned NV = Ptr.isBaseClass() ? 0 : Record->getNumVirtualBases();
R = APValue(APValue::UninitStruct(), NB, NF);
for (unsigned I = 0; I < NF; ++I) {
const Record::Field *FD = Record->getField(I);
QualType FieldTy = FD->Decl->getType();
const Pointer &FP = Ptr.atField(FD->Offset);
APValue &Value = R.getStructField(I);
if (llvm::Optional<PrimType> T = Ctx.classify(FieldTy)) {
TYPE_SWITCH(*T, Ok &= ReturnValue<T>(FP.deref<T>(), Value));
} else {
Ok &= Composite(FieldTy, FP, Value);
}
}
for (unsigned I = 0; I < NB; ++I) {
const Record::Base *BD = Record->getBase(I);
QualType BaseTy = Ctx.getASTContext().getRecordType(BD->Decl);
const Pointer &BP = Ptr.atField(BD->Offset);
Ok &= Composite(BaseTy, BP, R.getStructBase(I));
}
for (unsigned I = 0; I < NV; ++I) {
const Record::Base *VD = Record->getVirtualBase(I);
QualType VirtBaseTy = Ctx.getASTContext().getRecordType(VD->Decl);
const Pointer &VP = Ptr.atField(VD->Offset);
Ok &= Composite(VirtBaseTy, VP, R.getStructBase(NB + I));
}
}
return Ok;
}
if (auto *AT = Ty->getAsArrayTypeUnsafe()) {
const size_t NumElems = Ptr.getNumElems();
QualType ElemTy = AT->getElementType();
R = APValue(APValue::UninitArray{}, NumElems, NumElems);
bool Ok = true;
for (unsigned I = 0; I < NumElems; ++I) {
APValue &Slot = R.getArrayInitializedElt(I);
const Pointer &EP = Ptr.atIndex(I);
if (llvm::Optional<PrimType> T = Ctx.classify(ElemTy)) {
TYPE_SWITCH(*T, Ok &= ReturnValue<T>(EP.deref<T>(), Slot));
} else {
Ok &= Composite(ElemTy, EP.narrow(), Slot);
}
}
return Ok;
}
llvm_unreachable("invalid value to return");
};
// Return the composite type.
const auto &Ptr = S.Stk.pop<Pointer>();
return Composite(Ptr.getType(), Ptr, Result);
}
bool EvalEmitter::emitGetPtrLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
auto It = Locals.find(I);
assert(It != Locals.end() && "Missing local variable");
S.Stk.push<Pointer>(reinterpret_cast<Block *>(It->second.get()));
return true;
}
template <PrimType OpType>
bool EvalEmitter::emitGetLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
auto It = Locals.find(I);
assert(It != Locals.end() && "Missing local variable");
auto *B = reinterpret_cast<Block *>(It->second.get());
S.Stk.push<T>(*reinterpret_cast<T *>(B + 1));
return true;
}
template <PrimType OpType>
bool EvalEmitter::emitSetLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
auto It = Locals.find(I);
assert(It != Locals.end() && "Missing local variable");
auto *B = reinterpret_cast<Block *>(It->second.get());
*reinterpret_cast<T *>(B + 1) = S.Stk.pop<T>();
return true;
}
bool EvalEmitter::emitDestroy(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
for (auto &Local : Descriptors[I]) {
auto It = Locals.find(Local.Offset);
assert(It != Locals.end() && "Missing local variable");
S.deallocate(reinterpret_cast<Block *>(It->second.get()));
}
return true;
}
//===----------------------------------------------------------------------===//
// Opcode evaluators
//===----------------------------------------------------------------------===//
#define GET_EVAL_IMPL
#include "Opcodes.inc"
#undef GET_EVAL_IMPL